Method for making an ambient light curable ethylene propylene diene terpolymer rubber coating devoid of thermally activated accelerators

Abstract

A durable ambient light curable waterproof liquid rubber coating with volatile organic compound (VOC) content of less than 450 grams per liter made from ethylene propylene diene terpolymer (EPDM) in a solvent, a photoinitiator, an additive, pigments, and fillers, and a co-agent and a method for making the formulation, wherein the formulation is devoid of thermally activated accelerators.

What is claimed is: 
     
       1. A method for making a durable ambient light curable waterproof liquid rubber formulation with a volatile organic compound content of less than 450 grams per liter, comprising:
 a. blending in a closed vessel forming a solution, a first portion of ethylene propylene diene terpolymer (EPDM) with a first portion of solvent, wherein the ethylene propylene diene terpolymer (EPDM) is 50 weight percent to 99 weight percent of a total amount of ethylene propylene diene terpolymer used in a resulting durable ambient light curable waterproof liquid rubber formulation and the first portion of solvent is 33 weight percent to 67 weight percent of a total amount of solvent used in the resulting durable ambient light curable waterproof liquid rubber formulation; 
 b. mixing the solution in a high shear mixer for at least 10 to 240 minutes at a temperature from 20 degrees Celsius to 50 degrees Celsius forming a high viscosity solution; 
 c. adding a second portion of ethylene propylene diene terpolymer (EPDM) to the high viscosity solution, wherein the second portion of ethylene propylene diene terpolymer (EPDM) is 0.1 weight percent to 50 weight percent of the total amount of ethylene propylene diene terpolymer (EPDM) used in the resulting durable ambient light curable waterproof liquid rubber formulation; 
 d. adding a second portion of solvent to the high viscosity solution wherein the second portion of solvent is 33 weight percent to 80 weight percent of a total amount of solvent used in the resulting durable ambient light curable waterproof liquid rubber formulation; 
 e. blending the high viscosity solution for 10 minutes to 120 minutes at a temperature from 20 degrees Celsius to 50 degrees Celsius to form a low viscosity liquid intermediate rubber formulation with a saturated backbone of propylene, a saturated backbone of ethylene, and an unsaturated diene with ultra violet activated sites for crosslinking with or reacting with a free radical or a free radical on another terpolymer; 
 f. adding a co-agent to the low viscosity liquid intermediate rubber formulation to accelerate reaction of the free radicals with the active sites of the unsaturated diene to cross link the terpolymer, wherein the co-agent is 0.01 weight percent to 10 weight percent of the resulting durable ambient light curable waterproof liquid rubber formulation and the co-agent comprises at least one of: an acrylate, a triallyl cyanurate, a polybutadiene, and a phenylenedimaleimide; and 
 g. blending the low viscosity liquid intermediate rubber formulation with the co-agent at a low shear rate for 10 minutes to 120 minutes at a temperature from 20 degrees Celsius to 50 degrees Celsius in the absence of ultraviolet light; and 
 h. adding a photoinitiator devoid of thermally activated accelerators to the low viscosity liquid intermediate rubber formulation to generate free radicals that react with the active sites of the unsaturated diene, wherein the photoinitiator is 0.1 weight percent to 10 weight percent of the resulting durable ambient light curable waterproof liquid rubber formulation; wherein the photoinitiator is from 1 weight percent to 20 weight percent based on the total solvent content of the resulting durable ambient light curable waterproof liquid rubber formulation, wherein photoinitiators include Type I photoinitiators including: bis (2,4,6-trimethylbenzoyl)-phenyl phosphineoxide, and 1-hydroxy-cyclohexyl-phenyl-ketone; and Type II photoinitiators include benzophenone, alpha hydroxyl ketone, alpha amino ketone, isothioxanthone, and combinations thereof, and wherein all photoinitiators are devoid of thermally activated accelerators; and 
 i. forming a durable ambient light curable waterproof liquid rubber formulation devoid of thermally activated accelerators and adapted to crosslink and form a waterproof seal on a substrate only in the presence of ultraviolet light without the addition of heat. 
 
     
     
       2. The method of  claim 1 , wherein the first portion of ethylene propylene diene terpolymer has a different molecular weight than the second portion of ethylene propylene diene terpolymer. 
     
     
       3. The method of  claim 1 , comprising:
 a. adding to the high viscosity solution at a temperature from 20 degrees Celsius to 50 degrees Celsius, at least one of:
 (i) 50 weight percent to 99 weight percent of a pigment; and 
 (ii) 50 weight percent to 99 weight percent of a filler;
 wherein the amount of the pigment and the filler added represent a total weight percent of pigment and filler in the high viscosity solution; and 
 
 
 b. blending the pigment and filler to a particle dispersion from 4 to 8 units on the Hegman scale. 
 
     
     
       4. The method of  claim 1 , further comprising adding to the low viscosity liquid intermediate 0.1 weight percent to 10 weight percent of additives based on a total weight of the resulting durable ambient light curable waterproof liquid rubber formulation and the additives are at least one of: a hindered phenolic stabilizer or a hindered amine ultraviolet stabilizer. 
     
     
       5. The method of  claim 1 , further comprising: adding to the low viscosity liquid intermediate 0.1 weight percent to 10 weight percent of an adhesion promoter based on the total weight of the resulting durable ambient light curable waterproof liquid rubber formulation after adding the second portion of ethylene propylene diene terpolymer (EPDM) to the high viscosity solution, wherein the adhesion promoter is at least one of: a zinc diacrylate or zinc dimethacrylate. 
     
     
       6. The method of  claim 1 , further comprising: adding to the low viscosity liquid intermediate rubber formulation: 0.1 weight percent to 10 weight percent of a pigment dispersant based on the total weight of the resulting durable ambient light curable waterproof liquid rubber formulation, wherein the pigment dispersant is 1 methoxy-2-prop ylacetate. 
     
     
       7. The method of  claim 1 , further comprising: adding to the low viscosity liquid intermediate rubber formulation: 0.1 weight percent to 10 weight percent of an anti-settling agent based on the total weight of the resulting durable ambient light curable waterproof liquid rubber formulation, wherein the anti-settling agent is at least one of a hydroxyl ethyl cellulose and a fumed silica. 
     
     
       8. The method of  claim 1 , further comprising: adding to the low viscosity liquid intermediate rubber formulation 0.1 weight percent to 10 weight percent of a defoamer based on the total weight of the resulting durable ambient light curable waterproof liquid rubber formulation, and wherein the defoamer is at least one of: a polymethyl alkyl siloxane, a modified polysiloxane, and a polymethylsiloxane in a solvent. 
     
     
       9. The method of  claim 1 , further comprising adding to the low viscosity liquid intermediate rubber formulation 0.1 weight percent to 10 weight percent of an air release agent based on the total weight of the resulting durable ambient light curable waterproof liquid rubber formulation, wherein the air release agent comprises at least one of: a mineral oil, a paraffinic oil, a silicone oil, or a similar oil. 
     
     
       10. The method of  claim 3 , further comprising: adding 0.1 weight percent to 30 weight percent of a flame retardant to low viscosity liquid intermediate rubber formulation, based on the total weight of the resulting durable ambient light curable waterproof liquid rubber formulation, wherein the flame retardant comprises: an alumina trihydrate, by adding:
 a. with a member of at least one of: a pigment, a filler, and an additives to the low viscosity liquid intermediate rubber formulation; or 
 b. after the second portion of ethylene propylene diene terpolymer is added to the high viscosity solution. 
 
     
     
       11. The method of  claim 1 , further comprising: adding to the low viscosity liquid intermediate rubber formulation 0.1 weight percent to 12 weight percent of a wetting agent based on the total weight of the resulting durable ambient light curable waterproof liquid rubber formulation, wherein the wetting agent is at least one of: a silicone polyacrylate copolymer in solvent and a solvent-free polyether modified dimethylpolysiloxane. 
     
     
       12. The method of  claim 1 , further comprising: adding to the low viscosity liquid intermediate rubber formulation 0.1 weight percent to 10 weight percent of a biocide based on the total weight of the resulting durable ambient light curable waterproof liquid rubber formulation, wherein the biocide is a methylchloroisothiazolinone. 
     
     
       13. The method of  claim 1 , further comprising: adding 0.1 weight percent to 30 weight percent of a low molecular weight non-volatile plasticizer low viscosity liquid intermediate rubber formulation after the second portion of solvent is added to the high shear mixture, wherein the low molecular weight non-volatile plasticizer comprises: a paraffinic oil, naphthenic oil, plant based oil, diester oil, silicone oil, a mineral oil, a low molecular weight polyalphaolefin, or combinations thereof. 
     
     
       14. The method of  claim 1 , wherein the first portion of solvent and the second portion of solvent are selected from the group: mineral spirits and hexamethyldi-siloxane. 
     
     
       15. The method of  claim 14 , wherein the first portion of solvent and the second portion of solvent can be different solvents. 
     
     
       16. A method for making a durable ambient light curable waterproof liquid rubber coating formulation with a volatile organic compound content of less than 450 grams per liter, comprising:
 a. blending in a closed vessel forming a solution, a first portion of ethylene propylene diene terpolymer (EPDM) with a first portion of solvent, wherein the ethylene propylene diene terpolymer (EPDM) is 50 weight percent to 99 weight percent of a total amount of ethylene propylene diene terpolymer and the first portion of solvent is 33 weight percent to 67 weight percent of a total amount of solvent used in a resulting formulation; 
 b. adding to the solution:
 (i) 0.25 weight percent to 20 weight percent of a pigment based on a total weight of the resulting formulation; and 
 (ii) 0.25 weight percent to 50 weight percent of a filler based on a total weight of the resulting formulation to form a mixture; 
 
 c. mixing the mixture in a high shear mixer at a temperature from 20 degrees Celsius to 50 degrees Celsius until the mixture forms a grinding base with a Hegman scale value from 4 to 8 with dispersed pigment and filler; 
 d. adding a second portion of ethylene propylene diene terpolymer (EPDM) to the grinding base, wherein the second portion of ethylene propylene diene terpolymer (EPDM) is 1 weight percent to 50 weight percent of the total amount of ethylene propylene diene terpolymer (EPDM) used in a resulting durable ambient light curable waterproof liquid rubber coating formulation; 
 e. adding a second portion of solvent to the grinding base and blending until all components are uniformly blended at a temperature from 20 degrees Celsius to 40 degrees Celsius forming an intermediate, wherein the second portion of solvent is 33 weight percent to 67 weight percent of the total amount of solvent used in a resulting formulation; 
 f. adding 0.01 weight percent to 10 weight percent of a co-agent to the intermediate, wherein the co-agent is comprises at least one of: an acrylate, a triallyl cyanurate, a polybutadiene, or a phenylenedimaleimide, and blending the intermediate with the co-agent at a low shear rate for 10 minutes to 120 minutes at a temperature from 20 degrees Celsius to 40 degrees Celsius in the absence of ultraviolet light; and 
 g. adding 0.1 weight percent to 10 weight percent of a photoinitiator devoid of thermally activated accelerators to the intermediate and forming a durable ambient light curable waterproof liquid rubber formulation devoid of thermally activated accelerators, wherein the formulation is adapted to crosslink and form a waterproof seal on a substrate only in the presence of ultraviolet light.